1. Field of the Invention
The present invention relates generally to systems that clean (e.g., remove dirt, dust, rocks, etc. from) tires on vehicles such as a cars, trucks, tractor-trailer rigs, and the like.
2. Related Art
As equipment such as pickup trucks, dump trucks, concrete trucks, earth moving equipment, etc., leaves a construction site, the equipment can often carry with it dirt, mud, rocks and other debris that can be transferred to roadways adjacent the construction site, or can be released into the atmosphere as the vehicle's speed increases. This tracked-out debris, or “track-out,” can cause roadway hazards, and can also violate environmental protection regulations and other rules promulgated to reduce the nuisance of such track-out. For example, some air quality regulations, when combined with some storm water pollution rules, disallow virtually all track-out from construction sites. Track-out violations can result in fines being incurred by the general contractor or subcontractor, with fines sometimes escalating for each offense. Since eliminating track-out entirely is extremely difficult, if not impossible, fines can often be reduced by showing attempts at track-out prevention efforts.
Some of these track-out prevention efforts have included vacuum street sweepers, track-out rock pads and wheel washers. Each of these methods has proved problematic in one manner or another. For example, vacuum street sweepers don't prevent track-out, but instead clean up material already tracked out. Since it is the tracked out material that resulted in the regulations being violated, clean up alone does not prevent the violation, and in fact evidence of clean up can be regarded as evidence of a violation.
Track-out rock pads are shallow ditches filled with clean, loose gravel over and through which a departing vehicle traverses. As the vehicle tires move through the ditch, the loose rock in the ditch acts to dislodge material adhered to the tire. A permit is often required to operate such rock pads, and the rock pads often don't eliminate track-out completely. In fact, if a construction site is muddy, the gravel in the rock pad may increase track-out problems.
Both high pressure and low pressure wheel washers have been developed for removing track-out from construction vehicle tires. Some of these systems have proven effective in eliminating track-out, but usually require permanent structures with controllable site conditions and established roadways. Additionally, these systems are expensive and can actually promote track-out when water is not properly contained.